The present invention is directed to the field of hair care products.
Human hair, like animal wool, horn, nails, skin, and feathers, etc., comprises proteinaceous helices known as keratins. Such structural proteins degrade with prolonged exposure to sunlight, harsh chemicals such as dyes and bleach, and air-borne pollutants. Hair follicles also stop producing the requisite melanin as a person ages; thus, the hair turns gray. To preserve a youthful appearance or for fashion purposes, the cosmetic industry has developed conditioners and coloring agents for hair. In addition, fragrances and UV blockers have been incorporated into shampoos and conditioners to further impart desirable attributes. However, the technical approaches traditionally adopted to achieve these objectives have been developed in an ad hoc fashion.
Current hair dyes and dying systems involve harsh chemicals, such as oxidizing agents, to convert pigment precursors into colored species after such precursors are first applied to the hair. This basic approach requires the precursors to penetrate deeply into the hair shaft, whereupon the oxidative conversion takes place in a subsequent operation. Similarly, when lighter colors or shades are desired, the bleaching agents must diffuse deeply into the hair to destroy the intrinsic melanin deposits. Repeated dying or bleaching using harsh chemicals tends to damage the hair significantly. Scalp exposure to the chemicals also may induce allergic reactions in sensitive individuals.
This invention provides a systematic nanoscopic platform to enable a comprehensive list of hair care products. In one embodiment, this invention provides a technology platform for developing hair-coloring products that do not require oxidizing or bleaching chemicals. The nano-technology platform is based on an entirely different premise for coloring. In a similar manner, conditioning effects, UV-blocking abilities, and prolonged fragrance release can be achieved with this invention. The nano-technology platform offers advantages that have not been achievable by other means to date.
More particularly, this invention is directed to a hair treatment preparation comprising a dye or other payload with an intimate relationship to a polymeric nanostructure, the nanostructure having hair-reactive functional groups or other characteristics that allow it to be covalently bound to or otherwise immobilized onto or in the hair. This invention describes a systematic approach where nanoscopic objects or structures are either shaped as a miniature sphere or particle that can be attached to a hair, referred to herein as a xe2x80x9cnanospherexe2x80x9d or a xe2x80x9cnanoparticlexe2x80x9d; or as an invisibly small, molecular-dimensioned net surrounding a hair, referred to herein as a xe2x80x9cnanoscopic macromolecular networkxe2x80x9d or xe2x80x9cnanoscopic polymer networkxe2x80x9d.
The nanospheres and nanoscopic networks are constructed out of polymeric materials, which can be either naturally occurring or synthetic. The natural kind can be modified or derivatized by well-established organic chemistry. The synthetic type can be specially designed to exhibit custom-tailored properties.
The above geometries are merely examples of the whole spectrum of nano-technology that is applicable to the hair product industry. Many variations of the two basic schemes can be envisioned and are intended to be covered by this invention. For example, mixtures of nets and spheres can be developed to give more than one attribute per treatment. In addition, the nets can be fully crosslinked (either chemically or physically) or partially crosslinked. They can even be an entangled but not crosslinked network. The net may further be attached to the hair or to another polymeric species deposited on the hair surface at sparsely distributed points, so that the molecular network resembles a collection of nanoscopic whiskers. The spheres may be formed as micelles, where a group of surfactant molecules capture a payload, the resulting micelle being crosslinked after or upon deposition onto hair through a mordant or a polyelectrolyte.
Regardless of the geometrical features, the nanoscopic nature of the entities being engineered ensures three distinct characteristics. First, the imparted attribute can be either nearly permanent or semi-permanent, depending on the attachment chemistry. In the semi-permanent version, the intended effect can be controllably erased by removal of the nano-structure by simple chemical or physical means. Second, the nanoscopic entities are invisibly small. Their presence does not deteriorate the hand or feel of the hair. The impact of the nanoscopic objects or structures can at most be felt as enhanced smoothness or softness. Third, the nano-technology approach is infinitely flexible and adaptable. It can be coupled with many existing dyes, colorants, UV absorbers, fragrances, and softening agents for hair treatment.
The present invention is further directed to methods of treating hair which comprise applying a hair treatment preparation to the hair, the hair treatment preparation comprising a payload in an intimate relationship to a polymeric nanostructure, the polymeric nanostructure being reactive to hair or capable of being immobilized onto or in the hair; and changing the conditions such that the payload and nanostructure are attached to the hair.